Air conditioning system



Nov. 21, 1944. w. H. CARRIER 2,363,294

AIR CONDITIONING SYSTEM Filed Aug. 12, 1939 5 Sheets-Sheet 1 INVENTORWalks )1 Carrier BYMQQJ ATTORNEY NOV. 21, 1944. w, ARR|ER AIRCONDITIONING SYSTEM Filed Aug. 12, 1959 5 Sheets-Sheet 2 INVENTOR W1Zlas H Caz-Iver BY 31 g ATTORNEY Nov. 21, 1944. w. H. CARRIER 2,363,294

AIR CONDITIONING SYSTEM Filed Aug. 12, 1959 5 Sheets-Sheet 5 150a J48INVENTOR W W 54 M11155 [1. Carrier 63 67 1 mph ATTORNEY Nov. 21, 1944.w, CARRIER 2,363,294

AIR CONDITIONING SYSTEM Filed Aug. 12, 1939 5 Sheets-Sheet 4 INVENTORm'llds' H Carrier BYM W ATTORNEY Patented Nov. 21, 1944 AIR CONDITIONINGSYSTEM Willis 1!. Carrier, Syracuse, N. Y., assignor to CarrierCorporation, Syracuse, N. 1., a corporation of Delaware ApplicationAugust 12, 1939, Serial No. 389549 3 Claims.

This invention relates to air conditioning.

The general object of the invention is to provide an improved method ofand apparatus for air conditioning a plurality of areas or enclosures,and more particularly the various rooms of oflice buildings, schools,hospitals, apartments, hotels and the like.

It is an object of the invention to provide a method of and apparatusfor conditioning air adapted to provide required cooling under summeroperating conditions and required heating under winter operatingconditions, while at all times maintaining a desired dewpoint oratmospheric moisture content within the conditioned enclosures.

It is another object of the invention to provide an improved airconditioning system capable of providing for desired conditioning duringwinter and summer seasons, and also, during intermediate seasons, ofoperating in such manner as to simultaneously heat and cool differentenclosures served thereby whenever such differential action is requiredby load conditions affecting the several enclosures served by thesystem.

It is another object of the invention to provide an improved airconditioning system which assures positive and adequate ventilation atall times of the areas or enclosures served thereby.

It is another object of the invention to provide an air conditioningsystem employing a plurality of local units severally disposed in orproximate the areas which are to be served by said un ts, said unitscontaining no motors, compressors, fans or other apparatus of a similarnature, and being entirely free of moving parts, thus giving assuranceof long life, silent operation and freedom from operating diilicultiesand mechanical break-downs.

It is another object of the invention to provide an air conditioningsystem which is particularly well adapted for installation in existingstructures at relatively low cost, and which also is well adapted forinstallation in new structures.

It is another object of the invention to provide an air conditioningsystem for conditioning a plurality of areas or enclosures in which aportion of the air delivered to said areas or enclosures is conditionedat a central point, but in which the distribution of such air iseffected without resort to conventional ducts of large sizes, the airconditioned at the central point in accordance with the presentinvention being supplied through conduits of relatively small dimensionsand occupying relatively little space. In oilice buildings and the like,where space is at a premium and rentals are based on the floor areaavailable for useful purposes, the saving of space eflfected by thepresent invention is of great importance.

It is another object of the invention to prouide an improved airconditioning system for conditioning a plurality of enclosures in whicha portion of the required conditioning is eifected at a centralconditioning point remote from the enclosures and the remainder of therequired conditioning is effected by apparatus of the unit type disposedin and serving the various enclosures conditioned by the system.

Broadly stated, the invention includes conditioning to a desired degreea first volume of air at a central conditioning point, and distributingthis air at relatively high static pressure and at relatively highvelocity to a plurality of units respectively disposed in and serving aplurality of areas or enclosures to be conditioned. The high pressureair supplied to each unit is discharged therein through nozzleformations or the like, and in this manner induces a relatively greatsecondary circulation of air withdrawn from the area served by the unit.The primary or high pressure air and the secondary or induced air arethen supplied to the conditioned area. Preferably, the primary air isconditioned to a predetermined dewpoint at the central conditioningpoint, and tempering means, such as coils or the like, are disposed inthe various local units to effect sensible cooling or heating of aircirculated through the unit as required. The primary air preferablycomprises outdoor air, and since in carrying out the invention it ispreferred to use approximately one part of primary air for each fourparts of secondary air supplied to each conditioned enclosure, adequateventilation of the enclosures served by the system is thus assured.

These and other features, objects and advantages of the invention willmore fully appear from the following description to be read inconnection with the accompanying drawings, in which:

Fig. 1 is a diagrammatic view illustrating an air conditioning systemembodying the invention;

Fig. 2 is a front elevational view, partly in section, of one of thelocal units adapted to be emplayed in carrying out the invention;

Fig. 3 is a view of the unit of Fig. 2 taken on the line 3-3 thereof;

Fig. 4 is a view in plan of the unit of Figs. 2 and 3, part of thecasing being broken away to show the interior of the unit Fig. 5 is aview illustrating, in section, a valve adapted to modulate the coolingor heating action of the local units in response to changes in loadrequirements, and diagrammatically illustrates the piping connections toand between this control valve and the heat exchange coil of theconditioner unit;

Fig. 6 is a fragmentary view in end elevation of the interior of a unitin accordance with the invention, illustrating an indicator mechanismadapted to be employed when control of the local unit is effectedmanually rather than automatically;

Fig. '7 is a view in plan of the control mechanism shown in Fig. 6;

Fig. 8 is a view in perspective of a portion of the control mechanism ofFigs. 6 and 7;

Fig. 9 is a fragmentary view, in perspective, of a riser employed incarrying out the invention, and a lateral connection thereto, the latterbeing shown in an exploded view;

Fig. 10 is a view in vertical section through an assembled lateral airconnection, taken on the line Iii-l0 of Fig. 9;

Fig. 11 is a view on an enlarged scale, taken on the line I l-ll of Fig.9, illustrating the joint formation in the vertical riser;

Fig. 12 is a view in horizontal section through one of the channelshousing the air riser and water supply. return and drain pipes, whichextend upwardly from the central station appa ratus for connection withthe various local units of the apparatus;

Fig. 13 is a view in vertical section of a baseboard constructionadapted to contain and conceal the laterally extending air conduit,water supply, water return and drain pipes, taken on the line l3ll ofFig. 14;

Fig. 14 is a view in perspective of the corner of an enclosure served byapparatus in accordance with the invention, illustrating the baseboardassembly;

Fig. 15 is a view in perspective, of a baseboard spacer element;

Fig. 16 is a view in vertical section through a manual control valveadapted to be employed in carrying out the invention, and incorporatinga modified indicator mechanism in conjunction therewith; and

Fig. 17 is a view in plan of the control knob of the apparatus of Fig.16.

Referring now to the drawings, similar numerals referring to the same orsimilar parts, the numeral designates generally a casing containing airconditioning apparatus of any desired type, and disposed at any desiredpoint in or proximate a building to be conditioned. Thus, for example,the casing 25 may be disposed in the cellar, attic or storage space of abuilding served thereby. A fan 26 draws air through the casing,preferably from the outdoor atmosphere, whereby the air is conditionedin desired manner during its passage through the casing 25. and thendischarges this air at relatively high static pressure into the primaryhigh pressure air main TI.

The conditioning apparatus in casing 25 may be of any desired type andit is to be understood that the invention is not limited with respectthereto. As illustrated, however, the conditioner casing 25 preferablyincludes a filter 28, a cooling coil 2! and a reheating coil 30. Coldbrine or other suitable conditioning medium is supplied to the coil 29through supply line BI and is withdrawn therefrom through return line 32under the influence of pump 33 which returns the liquid through strainer34 to a cooler 35, of any desired type, from which the cooledrefrigerant is returned to line 3|. Any desired means may be used toregulate suitably the temperature of the cooled refrigerant. Reheatingcoil 30 receives a heating medium, such as steam, from supply main 36through branch line 31 under the control of valve :8 controlled bythermostat 39. The valve 38 admits steam to the coil 30 in a quantitysumcient to maintain the temperature of the air leaving the casing 25 ata desired point, thus reducing the relative humidity of the air leavingthe cooling coil 29. Preferably the conditioner casing 25 contains alsoa preheating coil lll adapted to receive steam from main 38 under thecontrol of valve ll controlled by a thermostat 42 disposed within theconditioner casing, the preheating coil 40 being intended for use underwinter operating conditions. The conditioner casing preferably alsocontains humidifying sprays or the like 43 operative under winteroperating conditions to increase the moisture content of air passingthrough the conditioner casing.

The pipes 44 and 45, respectively connected to pipes 32 and 3 I, andrespectively served by valves 46 and 41, may be used for connecting intothe circuit of the cooling coil 29 a connection to a source of wellwater, ice-water storage tank, or a cooling tower or the like for usewhen the wet bulb temperature of the outdoor air is sufllciently low topermit the use of evaporative cooling instead of the refrigerationnormally supplied in any desired manner to the cooler 35. It will beunderstood that when the valves 46 and 41 are opened, the valves l8 and49, respectively located in lines 32 and 3|, will be closed.

Preferably a closed expansion tank 5|) is connected by line 5| to therefrigerant return line 32, the closed expansion tank containing aquantity of compressible medium such as air and being employed at a lowpoint in the liquid circulating system. It will be understood that ifdesired an open expansion tank may be used at a high level in the systemin the same manner as employed, for example, in connection with hotwater heating systems.

As noted above, control of the operation of the local units may beeffected either manually or automatically. For purposes of illustration,the section of the system indicated within the dotted lines anddesignated zone A in Fig. l of the drawlngs, will be described withparticular reference to automatic control, while the section of thesystem indicated within the dotted lines and designated zone B, will bedescribed with particular reference to manual control. It is to beunderstood that each zone of the conditioning system may comprise anynumber of local conditioning units, and that any number of zones may beprovided.

For purposes or simplifying control, it is preferable that the zones ofthe system be arranged in accordance with the heat loads affecting thediii'erent enclosures of the conditioned building. For example, in anoillce building all of the oilices having windows facing in an easterlydirection would be subject to the heating efl'ect of the sun early inthe day, whereas this heat load due to sun eflect will fall of! later inthe day. All or a number of such oillces might well be served, inaccordance with the invention, by local units comprising a single zone.In the same way the offices having windows facing in a southerlydirection are preferably served by units comprising another zone of theconditioning system, etc. Of course, other factors than sun eii'ect mayhave dominating importance in this connection. Thus, if certain roomsare ordinarily occupied in a great degree, whereas other rooms areordinarily occupied to a lesser degree, it might be desirable to arrangethe zoning of the various units with reference to these factors so thatdesired simplicity and uniformity of control may readily be achieved. Insuch case units having a high heat load would form one zone and unitshaving a low heat load would form another zone.

It is to be understood that the units comprising a zone of the systemmay be located on different floors, or on the same floor, or both, andthat any number of units may be incorporated within a zone. The natureof the zone controls and the interconnection of the various units withthe central station conditioning plant, will now be described in detail.

The air delivered by the fan 28 to the primary air distributing main 2!is at a relatively high static pressure, of the order of 5" of water. Aportion of this air is diverted from the primary main 21 and passes to avertical riser 52 of zone A and a corresponding riser 52' of zone B.Each vertical riser delivers air to a plurality of units designatedgenerally as 53, through lateral connections 54. The primary air thusdelivered to each unit serves to induce a relatively great circulationof secondary air and to promote desired circulation of air in theconditioned enclosures.

A pipe 55 connects with the cold water return line 32 and is adapted todeliver cold water or brine from said return line to cold water supplyheader 56, which, in turn, is adapted to supply this water to thedifferent local units 53 of the various zones.

Each zone is provided with a control instrument, generally designated51, which may be conveniently located at any desired point either withinor without the enclosures of the zone served thereby. In practice it hasbeen found expedient to position the control device 51 outside of thebuilding, or in such manner that it is subject to outdoor atmosphericconditions. Preferably, the control instrument 5! comprises a deviceknown as the Aerotherm, manufactured by Webster- Tallmadge & Co. Inc.Since this control device is well known in the art and does not, per se,form part of the invention, no detailed description thereof is deemedrequired here. It is to be understood, however, that the control device51 preferably responds not only to air temperatures, ut also to airvelocity, wind direction, etc., so that the device controlling each zonemay accurately reflect the need either for cooling or heating of theparticular zone served thereby, and may at least approximately indicatethe degree of heating or cooling which is required.

When the control device 51 serving zone A indicates a demand for coolingof the enclosures served by the local units 53 of zone A, control line58 leading from the control device 5! serves to open the three-way orproportioning valve 69 so that the pump 60 draws cold water from theheader 58 upwardly through pipe BI and delivers this cold water throughpipe 82 to the cold water riser 63. Under such operating conditions thecontrol device 51, through control line 84, operates to adjust theproportioning valve 85 in such manner that flow from the pipe 62 to thepipe 63 is unimpeded. Thus, cold water may be delivered from the pipe 83to each of the units it through lateral connections such as II, and thiswater may then be returned through pipe I to the cold water return line32 at the suction side of the pump 38. When the control device 1reflects a demand for maximum cooling, the valve 59 will be adjusted sothat the pump Bl draws water only from header 56. and in this case alsoall of the water returning from the local units through the pipe 0! willpass to the water return line I2. However, if the cooling load is lessthan maximum, the proportioning valve 59 will be adjusted to anintermediate position determined by the cooling load, in which the pump60 will draw water not only through pipe ll from the header 56, but alsothrough bypass line 88 leading from the water return line ll. It will beunderstood that the control device II, by varying the proportions ofwater drawn from the supply header 56, and from the return line 01, willeflect a variation in the temperature of the water delivered to theunits in accordance with variations in load requirements.

Under winter operating conditions, or whenever heating is required, asindicated by the control device 81, the proportioning valve It is soadjusted that the pump 60 draws water only through the bypass connection68 from line 61. The water then delivered from the pump passes to theproportioning valve 65 through line 82 or line 89, or both, in varyingproportions controlled by the valve 85 under control of device 51. Theline 89 contains a heater III which receives steam from header I8 underthe control of valve 1|, the valve ll preferably being controlled by thecontrol device I! as indicated by the dotted line 12 leading to thecontrol line 84. The valve H is normally fully open whenever heating isrequired, the modulation of heating effect being accomplished by therouting of diilerent portions of water through the heater 10 and throughthe pipe 82.

Under summer operating conditions the water discharged from the valve 65passes to the units through line 63 and is returned therefrom throughline 81. However, under winter operating conditions when automaticcontrol of the local units 53 is employed, as in zone A, it is preferredto reverse the circulation. Thus, under winter operating conditions, hotwater delivered from the proportioning valve 65 is routed throughcross-over pipe 12 to pipe 61 by suitable adjustment of three-way valve13, and water returning from the local units passes through pipe 63,thence through cross-over pipe 14 by suitable adjustment of three-wayvalve 15, and then returns to the inlet of pump 60 through line 68.

Suitable shut-off valves 16 and H are provided for isolating the entirepiping arrangement of each zone from the central conditioning apparatusif this should be desired.

Under winter operating conditions when no cooling is required, thecirculation through the cooling coil 29 of the central stationconditioner 25 is interrupted and in such case the shut-off valves I8and I! are closed to isolate the central station water circulatingsystem from the water circulating system of the various zones. However,under winter operating conditions, or whenever the central station watercirculating system is inoperative, the valve in line 8| is opened tomake available to the water circulating systems oi the various zones thefunction of the expansion tank ill. When the central station watercirculating system is operative and is operatively connected with thewater circulating systems of the various zones, valve 80 is closed.

The piping and control arrangement for zone B. in which the units arecontrolled manually, is substantially as described in connection withzone A, except that it will be noted that valves 13 and I5, and thecross-over pipes 12 and H, are omitted. In all other respects, thepiping arrangement and basic control scheme is the same as described inconnection with zone A, and therefore no detailed description is deemedrequired with respect to zone 13.

Referring more particularly to Figs. 2, 3 and 4, illustrating one of thelocal units adapted to be employed, the numeral 82 designates generallya cabinet having an air inlet grille 83 formed in the front upperportion thereof and extending across a major portion of the length ofthe casing. Also an air outlet grille 84, comprising a plurality ofvanes or louvres extending lengthwise of the casing, is provided in thetop of the casing 82. Formed within the central portion of the casing 82is an air plenum chamber 85 to which air is delivered through inlet 86from lateral connection 54 extending from one of the vertical highpressure air risers. A valve closure member 81, operating in conjunctionwith valve seat 88, serves to control the volume of air admitted withinthe plenum chamber 85 and to effect the desired degree of pressurereduction. The valve closure member 31 is adjusted by means of a valvestem 89 preferably threaded and secured in desired position by a pair oflock nuts so which are tightened after the bottom projecting portion 9|of the valve stem has been turned to provide the desired degree of valveopening. In operation, once the valve has been adjusted to provide thedesired static pressure within the plenum chamber, it remains fixed inposition. However, if it is desired for any reason to cut the unit outof service. the valve is closed so that no air will be dischargedthrough such unit, while the system is used for delivering high pressureair to other of the units continuing in active service.

Preferably, the interior of the plenum chamber 85 is provided with aplurality of sound absorbing baffles 92 constructed of any suitablesound absorbing material, which cause the air delivered to the plenumchamber to flow in a circuitous path to the top of the plenum chamber.

The top of the plenum chamber is provided with a plurality of extensionchambers 93 extending crosswise of the unit and spaced from each otheras best seen in Figs. 3 and 4. The tops of the chambers 93 preferablyslope downwardly toward the front of the unit. Each chamber 93 isprovided, at its upper extremity, with a plurality of spaced relativelysmall nozzles or orifices BI, in diameter or smaller, through which airis discharged upwardly at relativel high velocity. In accordance withprinciples which are well understood. the high velocity discharge of airthrough the nozzles 94 induces a relatively great circulation of airintaken within the unit through the inlet grille 83, the air dischargedat high velocity and the induced air mixing in a mixing chamber 95 andthen being discharged from the unit through the outlet grille ill. Theinduction of air within the unit and its discharge therefrom insureactive circulation in the enclosure served thereby.

To prevent drafts or spilllng" of cool air in the vicinity of the unit,there are provided a plurality of diffusion vanes 95 proximate thedisiii iii

charge outlet 84, and these are preferably arranged in a fan-shapedmanner at varying angles, as best seen in Fig. 2. The diffusion of airlengthwise of the unit by the vanes 96 serves effectively to insureequable conditions within the enclosure without danger of drafts causedeither by "spilling" or by impingement of the air stream against arelatively low ceiling or beam and resultant downward deflection. Whenthe unit is employed in the center of a. wall area the vanes aresymmetrically arranged as shown in Fig. 2, but if the unit is employedat the end of a wall area it may be preferred to have the vanes whichare closest the end wall vertical and the other vanes correspondinglyinclined, the vanes farthest from the end wall most closely approachinthe horizontal. While the vanes 96 may be formed in any desired manner,they are preferably punched from a solid plate 91, the resultantapertures 98 serving as air passages.

Within the casing 82 at the inside of the inlet grille 83 is disposed asuitable heat exchange means of any desired type for conditioning theair induced within the unit by the discharge of primary air from thenozzles 9|. Preferably, the heat exchanger comprises coil 9! providedwith suitable plate or spiral fins for increasing the efficiency of heattransfer. It is to be understood that if desired, the coil may be placedin the path of the primary air, as well as in the path of the inducedair.

In Figs. 2, 3 and 4 the piping and control arrangement shown is thatemployed when the unit 53 is controlled manually. Water supply lin 88extends within the unit from vertical riser 83 and passes to a shut-offvalve I00. Water return connection IUI returns to pipe 51 from valveI08. The valve Hill is a twin valve which serves to interrupt flowthrough both the supply line 56 and return line lOi by means of a singleadjustment of the valve stem N12.

The numeral I03 designates generally a control valve, the constructionand operating mechanism of which are described more fully hereinafter.For present purposes, however, it is suiilcient to understand that thevalve is provided with three connections-an upper connection Hi l, acenter connection Hi5 and a bottom connection I05. A water supply lineI01, constituting a continuation of the supply line 66, delivers waterto central connection ill! of the valve I03. Some of this water thusdelivered to the valve is discharged from the valve through pipe I08 andthus is delivered to the heat exchange coil 99. The water leaving thecoil is returned to return pipe I09 through a connection indicated atH0. Water which is not supplied to the heat exchange coil 99 aftersupply to the valve I03, is bypassed from the valve back to the returnpipe I09 through bypass return pipe lli, leading from valve opening Hi8.By regulation of the valve M3 by means of handle III, varyingproportions of the water delivered to the valve may be routed throughcoil 99 and through the bypass connection III. In any event, however,regardless of the adjustment of valve Hi3, water is supplied to eachunit through the supply pipe 66 and returned therefrom through thereturn connection IN at a constant rate. Thus, the friction losses aremaintained constant and the system therefore may be hydrostaticallybalanced to give results superior to those obtainable where the rate offlow to and from a unit is varied in accordance with load requirements.This latter operation may be employed if desired but it is to beunderstood that the operation described above, in which the systemremains balanced at all times, is preferable.

Preterably, the coil 99 is provided with an air vent or the like III atthe upper portion thereof to relieve air irom the system.

In the operation of the central station conditioning apparatus, theprimary air is reduced to a low dewpoint. when water or brine is usedfor this purpose in the manner illustrated in Fig. 1, the heat exchangesurface is so designed that the brine returning from the coil 29 is at ahigher temperature than the air leaving the conditioner casing 25. Sinceit is the brine from return line 32 which is supplied to the local units53 to eflect cooling thereat, it will be appreciated that the brinedelivered to the local units will generally always be above the dewpointof the air in the conditioned enclosures so that no moisture will becondensed in the local units. This is true in all cases except onstarting up of the system in a humid atmosphere or where there is arelatively high latent heat load in the conditioned enclosure tendingabnormally to increase the moisture content of the air therein.

To accommodate the water which from time to time may be precipitated bythe coil 99 there is provided a drain pan Ill adapted to catch any waterdripping therefrom. The front portion of the drain pan Ill dischargesthe collected moisture into a trough II! which slopes downwardly towardthe right hand side of the casing, as best seen in Fig. 2. From the lowpoint 01' the trough II5 a drain connection H9 conveys condensatedownwardly to an auxiliary condensate pan IIl which is disposed beneathall oi. the apparatus in the casing 82 to catch any condensate which maydrip therefrom. The bottom of the pan I ll slopes downwardly toward thefront 01' the unit and a drain connection I I9 conveys water therefromtor disposition in any suitable manner. Preferably, the drain pipesextend from the various local units to a suitable point of condensatedisposal in the manner indicated, for example, in Fig. 12. Thus, it isto be understood that the piping arrangement of Fig. i actually mightalso include the common drain pipes used for the various units. However,this reature has not been shown in Fig. l as it would tend unnecessarilyto complicate the showing of the invention made therein.

Referring more particularly to Fig. 5, the numeral I93a designates avalve capable oi automatically modulating the heating or cooling effectof the coil 99 of the local unit 59. The control element which ispreferably used in conjunction with the valve comprises a length offinned tubing II9 of the type commonly used in the construction 01' heatexchangers. The length of the control element may approximate 8" and thediameter of the tube may be oi the order of A". One end of the tube issealed and the other end connects with a pressure tub I29 which extendswithin the housing HI 0! the valve Ilila. The control element H9 isfilled with a volatile fluid adapted to expand and contract with changesin temperature, such as ether, and the control element H9 is placedwithin the casing 92 behind the air inlet grille 92 and in the path ofair intaken within the unit through said grille, so that the controlelement reflects the temperature within the enclosure served by theunit. The control element is preferably shielded in any desired mannerfrom th heating or cooling eflect of the coil 99 so as to insure moreaccurate control.

Through the top cap I22 of the valve there flanged disc or the like I29.The rod I28 is provided with a control handle 2 for use in adjusting thesetting 0! the valve.

The flange I24 is secured in a gas-tight manner to the upper extremity01' an expansible bellows I25, the lower extremity oi the bellows beingsecured in a fluid-tight manner to a disc I29. The pressure tube I29leads from the interior of the thermal element I I9 to the interior 0!the bellows I25 so that as the temperature afiecting the control elementIII is varied, the bellows I2! is caused correspondingly to expand andcontract. A stud I21 extends within the interior of the bellows todecrease the free volume in the bellows, as this insures a more promptand sensitive operation of the valve. The disc I29 is connected to a rodI29 extending downwardly therefrom and bearing a flange I29 at its lowerextremity. The rod I29 extends within a cup-shaped member I39 and theflange I29 provides for retention of the rod I29 within the member I99so that as the rod I28 is raised the member I29 will be raisedcorrespondingly. A spring l2l, extending between the bottom of disc I29and the top oi member I39, tends to maintain maximum separation of thesetwo elements. The lower portion of member I39 carries a disc Illa towhich there is connected. in a fluid-tight manner, a sealing bellowsI92, and also a rod I32 extending through a plate I34 to which thebellows I22 is connected. Thus, the operating fluid ot the thermalelement is prevented from escaping within the valve and also the wateror brine controlled by the valve is eflectively prevented i'rmn escapingwithin the valve.

The rod I39 bears downwardly upon a lever I29 pivoted at I36. The treeand of the lever I" bears downwardly upon a lever I91, pivoted at I98,at a point proximate the fulcrum I39. The lever I3! is adapted toactuate the valve stem I" which is operably connected through astarshaped guide I49 to a valve closure member Ill, comprising a pair 0!oppositely arranged faces I92. The arrangement oi levers Iii and I2! isemployed for the purpose of multiplying the motion of the primarycontrol rod. Thus tor a given movement of the valve rod III thecorresponding movement of valve rod I29 may be four or flve times asgreat. This amplification makes for increased sensitivity and refinementof control and makes it possible to maintain within very close limitsthe desired temperature in the conditioned enclosure.

Th valve seat serving the upper face I92 is iormed in a partition plateIll provided between the upper connection I94 and the center connectionI95 01' the valve. The seat I, cooperating with the lower face I42 ofthe valve member I, is disposed between the central connection I" andthe bottom connection I96 of the valve. Spring 5, operating on valveguide I49, biases the valve in an upward direction.

Under summer operating conditions, or whenever cooling is required, atemperature higher than that desired requires an increased flow orcooling medium through the valve. Under winter operating conditions,however, a temperature higher than normal calls for a decreased rate offlow of heating medium through the coil. To render the local unitentirely automatic so that its single valve may provide for the accuratecontrol oi temperature under both summer and winter operatingconditions, the flow oi conditioning fluid to and from the local unit isreextends adjustable rod I23 bearing against a versed as explained abovein connection with three-way valves 13 and II and cross-over connections12 and 14.

Fig. 5, in addition to illustrating the structure of the valve,discloses diagrammatically the piping arrangement at the local unitwhich is employed in the case automatic operation.

Under summer operating conditions, as explained in connection with Fig.l, cooling medium is supplied through line 63, and thus enters the valvethrough the central connection I". Assuming a demand for cooling toexist, the high temperature ailecting the control element II! will causedepression oi the valve III and thus some 0! the liquid entering thevalve at connection I will flow upwardly and out oi the valve through HMand through line I" to the heat exchange coil 99. The conditioningmedium passing irom the cofl is routed through line I48 to junction Iand then passes through pipe I50, containing check valve I500, to line61 and is thus returned from the local unit. The portion or theconditioning medium supplied to the valve which is not so routed, passesdownwardly in the valve past the valve seat I and is discharged throughconnection I06 to line I5I through which it passes to junction I49,where this fluid is joined with the fluid discharged from theconditioning coil 99 and is returned therewith to the lin 61. As moreconditioning is required under summer operating conditions, more coldliquid is circulated through the conditioning coil 99 and less isbypassed through Illi, and as less conditioning is required less coldliquid will be supplied to the coil 99 and more will be bypassed throughIIIG.

Under winter operating conditions reverse operation occurs, and in thiscase an increased temperature affecting the thermal control element Illresults in decreased supp y of conditioning medium, which is then at arelatively high temperature, to the conditioning coil. Under winteroperating conditions, conditioning medium is supplied through line 61and passes through the branch line I52 containing check valve I52a, tojunction I53. Part of the conditioning medium travels through the pipeI41 and enters the valve at connection Ill and passes downwardly thereinand is discharged from the valve through connection I05. The otherportion of the conditioning fluid passes from the junction I53 to theconditioning coil 99, is discharged therefrom through line I 48 andthrough connection ISI, and enters the valve at I" and is dischargedtherefrom through central opening IIIS together with the fluid which wasbypassed through connection I". As the temperature aflecting the thermalcontrol element H9 rises, the valve I will be lowered and hence more ofthe conditioning fluid will be bypassed from IN to I05, andcorrespondingly less or the conditioning fluid will pass through thecoil 99 and the lower portion of the valve from IIIB to I05. Conversely,if the temperature is lower than desired, more of the heating fluid willbe routed through the conditioning coil and a lesser quantity will bebypassed.

When the valve controlling the action oi the heat exchange coil 99 iscontrolled manually, ther is no necessity for reversing the flow of theconditioning medium through the pipes 63 and 81 as in the case ofautomatic control in the manner Just described, since an operator canreadily turn the valve in either direction as required to bring aboutthe desired change in the conditioning action. Thus, under summeroperating conditions, when the local unit is supplied with coolingmedium, ii the temperature In the enclosure served by the unit is toohigh the operator will depress the valve III so as to permit increasedflow oi. cooling medium irom opening III! to opening I serving the pipeI08, which delivers conditioning medium to the coil 99; and ii thetemperature is too low the operator will adjust the valve to raise thevalve member Ill so that a lesser quantity 0! cooling medium flowsthrough the conditioning coil 89. Under winter operating conditions,when heating medium is supplied to the conditioning unit, the operationis merely reversed. Thus, when the temperature in the enclosure is toohigh, the operator will raise the valve Ill to diminish the supply ofheating medium to the coil 09 through the pipe IIIII, and ii theconditioned enclosure is too cold, the valve Ill will be depressed topermit a greater supply of conditioning medium to the coil 99 throughthe connection I08.

During intermediate seasons, however, certain operating difllcultiestend to arise. Thus, under certain conditions some 01' the zones of aconditioned enclosure may require heating while others require cooling.Under such conditions the central station apparatus would be operativefor supplying cooled and dehumidifled primary air to all zones, but thelocal zone control device 61 might cut oil the supply of cooling mediumto a zone requiring heating and instead might turn on the steam to warmthe water circulated to and through the local units of such zone. Undersuch circumstances an operator seeking manually to adjust the valvemight have some difllculty in determining whether the unit was beingsupplied with hot or cold water. Thus, it the operator put his hand overthe air outlet grille of a unit supplied with hot water, he mightexperience a sensation of cooling arising from the relatively lowdewpoint of the air and its rela- 4c tively high velocity, although thedelivered air 6 too warm, he would naturally open the valve wider, If infact the unit was being supplied with warm water, such increased openingof the valve would naturally aggravate his discomfort. Thus, there isindicated a need for a device which will positively indicate to theoperator the direction in which the valve should be adjusted to producea desired change, so that under both summer and winter operatingconditions, and regardless of whether the unit is being supplied withwarm water or cold water, the operator will at all times be enabled tomake the required adjustment promptly and without experimentation.

To this end there is preferably provided an arrangement such asillustrated in Figs. 6-8, which automatically indicates the direction inwhich the valve should be turned to provide i'or desired regulation ofthe room temperature, regardless of whether the unit is being suppliedwith hot water or cold water.

As illustrated, a thermal bulb IE4 is placed in heat exchange relationwith the water supply pipe W1. A pressure control line I leading fromthe thermal bulb I communicates with the interior or an expansiblebellows I56. The expansible bellows I56 carries a slide plate I61bearing suitable indicia indicated at I58. The slide plate I51 may besupported by suitable flanges or the like I59 and the plate IBI ismounted just beneath the top I 0! the conditioner casing, preferably atan end thereof. In the top or the conditioner casing are provided aplurality of apertures. one of these being designated it! and the otherI62. When the unit 53 is being supplied with cold water, the bellows I56will be relatively contracted and the marking W" or "Warmer" or the likemay then be visible through the aperture it! while the marking "C orColder or the like may be visible through the aperture "52. Thus, undersummer operating conditions, or when cold water is being supplied to theunit, the operator will turn the valve handle H2 in a clockwisedirection as seen in Fig. 7 to increase the cooling eifect, and in acounterclockwise direction as seen in Fig. '7 to decrease the coolingeffect. Under winter operating conditions, or when heating medium isbeing supplied to the local unit 53, the bellows I56 will be caused toexpand. This will move the slide I51 and the indicia visible through theapertures I and I62 will therefore be reversed. Therefore, if anoperator under winter operating conditions feels too warm the valvehandle I II will then be turned in a counter-clockwise direction as seenin Fig. 7 to increase the conditioning efl'ect, and if he feels too coolthe valve handle will be turned in a clockwise direction as seen in Fig.7. As will be understood, the valve handle is so arranged thatadjustment of the handle in accordance with the position of slide I51will effect the required adlustment of valve closure member I.

It is to be understood that the adjustable indicator mechanismillustrated in Figs. 6-8 is employed only because the direction of flowof the conditioning medium is the same regardless of whether theconditioning medium is hot or cold. If desired, the cross-over pipes 12and I4, and the three-way valves 13 and 15 described in connection withzone A of the system, may be incorporated in zones such as B in whichthe local units are manually controlled, and'in such case there will beno need for providing the adjustable indicator mechanism of Figs. 6-8which changes its position in accordance with the temperature of theconditioning medium. If the changeover arrangement is employed forreversing the flow in accordance with whether heating or cooling isbeing eflected by the conditioning medium, an operator will always turnthe valve in one direction if the enclosure served by the unit is toowarm, and will always turn the valve in the opposite direction if theenclosure served by the unit is too cold.

It is to be understood, moreover, that while the valves 13 and 15 havebeen described as beins three-way valves, the reversal of flow may beeffected by the use of ordinary shut-oil valves arranged in a mannerwell understood in the piping art. These change-over valves may becontrolled manually but preferably are arranged automatically to changetheir position in accordance with I the temperature of the conditioningmedium made available for delivery to the local units of any zone, andas explained above, the temperature of the conditioning medium madeavailable for supply to any particular zone is controlled in accordancewith the particular requirements of that zone. Thus, cold water may becirculated through some of the zones while hot water is circulatedthrough other of the zones. Since any well-known means may be used foreflecting the adjustment of the changeover valves in response to changesin the temperature of conditioning medium made available for supply tothe zones served thereby, no detailed showing of such control apparatusfor the valves is deemed necessary here.

Referring now to Fig. 9, which illustrates a section of one of the highpressure air risers, and a portion of a lateral connection extendingtherefrom, the latter being shown in an exploded view. 52 designates thevertical riser which replaces, in

the present invention, the relatively large and expensive distributionducts of conventional air conditioning systems. The riser pipe I: is ofrelatively small dimensions and comprises a tube of suitable metal orthe like. It may comprise. for example, a welded tube of galvanizedsteel. While it is to be understood that the size of the riser 52 willvary in accordance with the requirements of particular installations,and the amount of air a particular section is required to handle, thediameter of the riser pipe will generally be of the order of about 6".This is in marked contrast to the relatively large ducts required inconventional systems for distributing conditioned air from a centralconditioning point to a plurality of remote enclosures served by thesystem. Thus, these conduits have an area of only about '7 to 10% of thearea occupied by conventional ducts. Also, it will be appreciated thatinstallation and assembly of risers comprising sections of pipe, such as52, may be accomplished quickly and readily at relatively low cost. Thevertical risers are assembled from separate sec tions which are joinedtogether by suitable joints such as illustrated at ill, the preferredmanner of Joining the various sections of the riser 52 being shown moreparticularly in Fig. 11.

The exploded view portion of Fig. 9 and Fig. 10 illustrate a preferredmethod of connecting the lateral air connections 54 to the high pressureair risers. As illustrated, a pipe nipple I8! is welded to the riserpipe 52, the latter having a suitable opening i63 formed therein. Thepipe nipple I82 is externally threaded, as indicated at I84, and isinternally recessed so as to receive therewithin a flexible conduit I85of any desired construction. Preferably, the flexible conduit is of thetype illustrated in Fig. 10 which is well known in the art. I66designates a gasket of any suitable compressible material, preferablyneoprene, and I" designates a metal follower ring, preferably formed ofbrass or the like, which abuts the gasket and causes the latter to bearagainst the outer end of the pipe nipple I62. A screw cap I81 having aninternally threaded cylindrical flange, engages the threads of the pipeI62 so as to take up on the follower ring and gasket. The other end ofthe flexible conduit IE5 is suitably secured to the laterally extendingtube I68 which extends to the unit or units served by the lateralconnection enerally designated 54. Preferably, the flexible conduit issecured to the pipe I 88 by being soldered thereto at I59 and by meansof rivets or the like indicated at I".

It is to be understood that the primary air within the risers 52 must atall times be at a static pressure which is sufficiently high so thatnote withstanding friction losses and pressure drops throughout thesystem there may be a sufficient pressure available at the local unitmost remote from the central station for providing the desired inductioneil'ect when the high pressure air is discharged within the local unit.Thus, it will be apparent that at intermediate local units the pressurein the riser pipe will be too high to provide the desired inductioneffect. Delivery of air within the unit at too high a pressure resultsin excessive velocity, noisy discharge, and an excessive rate of aircirculation. Therefore, it is necessary to provide suitable means forreducing the pressure of the primary air which is delivered to thevarious local units.

In operation, the pressure in the primary air riser may be of the order01' 4" of water, whereas the optimum pressure within the plenum chamber85 of each local unit will preferably be of the order of about i" ofwater. To accomplish the necessary reduction of pressure in a noiselessmanner, the pressure is preferably reduced in stages. To this end thereis provided an orifice ring I" within the pipe nipple I62. The orificering "I has a relatively small opening I12 formed therein, the size ofthe opening being determined in accordance with the amount of pressurereduction which is to be effected by the orifice ring. As will beunderstood, the smaller the opening the greater will be the pressurereduction. The additional or secondary stage of pressure reduction isaccomplished by the valve 81 disposed at the air entrance I. to theplenum chamber of each local unit. Reduction of the pressure in thismanner assures simplicity in construction and quietness and efficacy inoperation. Where there is a relatively small pressure differentialbetween the pressure in the air main and the desired pressure in theplenum chamber of a local unit, and where the air valve at the unit maybe depended upon to accomplish the required pressure reduction in asatisfactory manner, the orifice ring may be eliminated from the lateralconnection serving such unit. This is often true in the case of unitsremote from the central conditioning apparatus.

Referring more particularly to Fig. 11 illustrating the manner in whichthe various sections of the riser 52 are assembled, the section 52a ofthe riser pipe 52 is belied at its upper extremity as indicated at I13,and the upper section 52b of the riser pipe 52 is disposed within thebelied portion I13 of the lower section. The bottom extremity of thesection 521) is preferably belied slightly outwardly as indicated atI14, the portion I'll abutting the shoulder I15 formed at the bottom ofthe belied portion I13. An air-tight and mechanically strong joint isassured by the provision of a wedging member generally designated I18disposed between the belied portion I13 and the lower portion of thepipe section 521). The inner surface of the wedging member I18 iscylindrical but the outside thereof is tapered to conform to the taperat the inside of the belied portion I13. The bottom portion I11 of thewedging member I16 is continuous, as is also the intermediate sectionI18 which is formed with a somewhat smaller outer diameter than thelower section I18 to provide a groove I19. The upper portion I80 of thewedging member I18 is provided with a plurality of vertically extendingslits I8I. By forcing the wedging member I16 tightly within the spacebetween the belied portion I13 and the lower portion of section 52b, anair-tight and mechanically strong joint may be effected readily andquickly, without resort to solder or any other bonding or sealingmaterial.

Fig. 12 is a horizontal section taken through a vertically extendingassembly used for containing and concealing the riser pipe 52, the watq'circulation pipes 63 and 81, and a suitable drain pipe I82 communicatingwith the drain pipes II8 of the local units. All of the verticallyextending pipes and conduits are contained within a suitable housinggenerally designated I83 which comprises a structural section I and anouter portion III of iinishing plaster or the like. It will be notedthat the connecting pipes 68 and IIII of the water circulating systemconnecting with the water circulating riser 63 and 81 are loop'ed aroundthe air riser 52 so that the bends thus formed in these connecting pipesmay provide for suitable expansion and contraction due to changes intemperature of the circulated condltioning medium. Preferably, the watercirculating pipes are insulated in any suitable manner.

It will be understood that the vertical risers will not always be inimmediate proximity to the local units, and it will therefore berequired to run short lateral connections from the vertical riser andwater pipes to the local units. In order that these laterally extendingconnections may be concealed from view, there is provided the baseboardarrangement illustrated in Figs. 13-15. As shown, a plurality ofbrackets I88 are secured to the wall of a room in any desired manner, asby screws I81. The upper extremities of the brackets I86 are providedwith belied portions I88 behind which there is adapted to be positionedthe downwardly extending flange I88 of a baseboard cover piece I90. Thelower portion of the cover piece is received within a pocket formedbetween an upwardly extending leg I9I of the bracket and a beliedportion I92 of an upwardly extending member I83 suitably secured in anydesired manner to the leg I8I of the bracket. Within the space thusformed there is also inserted the downwardly extending flange I9! of abase protecting plate I formed of suitable material adapted to withstandthe corrosive action of cleaning agents which might come in contacttherewith when the floors of the conditioned enclosure are cleaned.Mounted within the channel formed by the cover plate I98 is a draintrough I96 secured, as by screws I81, to the brackets I86. Over thedrain pan I98 is positioned the laterally extending air connection BIand the water connections 65 and IIII. Thus, any moisture which mightpossibly be precipitated within the baseboard conduit is adapted to becaught by the drain pan I88, which may deliver the condensed moisture todrain pipe II8 as by means of a suitable connection I98. It will beappreciated that the cover piece of the baseboard assembly may beremoved very readily to provide immediate access to the lateral air andwater connections. Also, the baseboard assembly may be installed veryquickly and conveniently and with the assurance that the assembly aftercompleted will provide a finished and attractive appearance and willeffectively conceal the lateral pipes connecting the unit with thevertical r ser.

When it is necessary to extend the lateral connections to a wall orpartition, this may be accomplished neatly by means of the finishingpiece I99 illustrated in Figs. 14 and 15. The finishing piece may beused in conjunction with a conventional wood molding 280 so that thefinished assembly will be entirely attractive as well as mechanicallysatisfactory.

If desired, a small quantity of the air conditioned in the centralstation conditioning apparatus may be discharged within the space "Isurrounding the vertically extending air risers and water connection anddrain pipes. As will be understood, the air thus conditioned has arelatively low dewpoint and hence effectively prevents condensation uponthe outer surfaces of the water supply or other pipes of the risersystem. As pointed out above, the dewpoint of the air conditioned at thecentral station will generally be lower than the temperature of thewater supplied to the local units for cooling purposes and thisrelationship practically precludes any possibility of condensation afternormal operating conditions have been established. Condensation willtend to occur only when the system is placed in operation in a humidatmosphere or when there is an abnormal increase in the moisture contentof the atmosphere surrounding the pipes of the riser system or in theconditioned enclosures.

Preferably, the front or the plenum chamber of each local unit isprovided with a removable plate 202 so that if, for any reason, accessto the interior of the plenum chamber should become necessary. as forpurposes of inspection, cleaning or repair, such access may be hadconveniently.

Figs. 16 and 1'! illustrate a valve construction adapted to be employedwhen manual control of the heating and cooling at the local units isdesired. Such a valve is indicated at I08 in Figs. 2 and 3 and also inFig. 6, except that the valve in Fig. 6 does not include the indicatormechanism disclosed in Fig. 16. The valve I03 is essentially the same asthe valve illustrated in Fig. 5 except for the omission of theexpansible bellows and the multiplying mechanism which heeomeunnecessary and may be eliminated in the case of manual operation. Thus,the valve includes a, casing l2l, a top cap I22 and an actuating steml23a, the valve stem lilo being hollow to provide a longitudinallyextending channel 203 therewithin. The bottom of the rod I230 bearsagainst an adjustahly positioned plate I! la and is adapted to causedisplacement of this plate. The plate Illa is connected to the partitionplate I by a sealing bellows I32, as in Fig. 5. A rod Ilia extendsdownwardly from the plate Illa and is movabl therewith to actuate thevalve closure member Ill. The plate ills is provided with a centralopening 204 and the rod liila is provided with a channel 204 extendingtherewithin and constituting an extension through the plate Illa oi thechannel 203 within the valve stem i224. The handle I l2a is secured tothe valve stem i214: in any desired manner as by means of a set screwIll so that as the handle is rotated, the valve stem is correspondinglyrotated and raised or lowered by means of the threads 206 to provide thedesired adjustment of position of the valve closure member Ill.

Within the channels 2 and 204 there is positioned the stem 201 01' athermal indicator having a rotating disc Ill mounted at the top thereofand within a recess formed in the top of the handle "2a. The recess iscovered by a closure plate 210 which is provided with an aperture 2through which a portion of the indicator plate 208 may be seen. A screwIII, or similar means, is employed to rotate the stem oi the thermalindicator as the handle Illa is rotated so that the relative positionsof the indicator disc 208 and the valve handle 2a may remain unaflectedexcept by changes in temperature afl'ecting the stem 201. Since thermalindicators of this type are well known in the art and in themselves donot constitute a part 01' the present invention, no detailed descriptionthereof is deemed required here. One type of thermal indicator of thecharacter indicated is manufactured by the Weston Electrical InstrumentCompany of Newark, New

Jersey. the instrummts manufactured by this 16 company, however, beinggenerally provided with a dial pointer rather than a disc as heredisclosed. As will be understood, the thermo-responsive stem 207,extending within and through the body or the valve, will respond tochanges in the temperature of the fluid passing through the valve andthus will change the position of the disc 20!! in accordance with suchchanges in temperature. Theupper face of disc 20! is provided with twosets of arrow indicators pointing in opposite directions and arrangedthroughout different arcuate portions of the indicator disc. When theconditioning medium circulated through the valve is cold, one portion ofthe indicator disc 268 will appear opposite the aperture 2, this portionbearing the arrows H3. The word Colder" appears upon the cover disc 2l0proximate the aperture, and when the arrows 2l3 are visible through theaperture 2| I, this will indicate that to provide cooler conditions inthe enclosure the valv handle should be turned in a clockwise direction.This will depress the valve closure member Ill and permit moreconditioning medium to enter the pipe I20 and thus pass to theconditioner coils. It the room is too cool under such operatingconditions the valve will be turned in a reverse direction to diminishthe amount of cooling medium passing to the conditioning coil. When theconditioning medium supplied to the valve is warm another portion of theindicator disc 208 will appear through the aperture 2| I, the arrows 2then indicating the direction in which the valve should be turned toprovide a. desired change in temperature within the enclosure.

Thus, when heating medium is supplied to the valve, turning the valve ina counter-clockwise direction will render the enclosure cooler byraising the valve closure device Ill and diminishing the supply ofheating medium to the conditioner coils, whereas turning the valvehandle in a reverse or clockwise direction will depress the valveclosure member Ill and cause more heating medium to pass to theconditioner coils. It will be apparent to those skilled in the art, thatinstead of the word "Cooler" the word Warmer" might be applied on thevalve handle, in which case the arrows will each point in a directionopposite to that shown in the drawings, and that variations may be madein the physical embodiment of the invention without departing from theconcept herein disclosed.

It will be observed that the system as above described is adaptedreadily to be installed in existing structures, particularly in thoseprovided with the piping lines customary in steam heating and hot waterinstallations, and that it is also well adapted to be installed in newstructures. The installation of the system in either case is facilitatedby the use of the high pressure piping for conveying the primary air atrelatively high pressure and at a velocity which may be of the order of3000-5000 feet per minute instead of the conventional ducts which occupya vastly greater amount of space.

Because the number of local units in operation may vary from time totime, it may be desired to employ a static pressure regulator formaintaining a substantially constant pressure in the primary air mainsby throttling the supply of air to the mains from the primary fan, orvarying flue effectiveness of the fan by varying its speed, or by bothmethods in combination. Since static pressure regulators operating inthis way are well known in the art and do not, per se, form part or theinvention, although desirable to:- use in connection therewith when thenumber of units in operation is considerably varied from time to time,no detailed description thereof is deemed required here.

Since many changes may be made in the invention without departing fromthe scope thereof, it is intended that all matter set forth in the abovedescription, or shown in the accompanying drawings. be regarded asillustrative only and not in a limiting sense.

I claim:

I. In an apparatus of the character described for conditioning aplurality areas, a conditioner remote from said areas, means forsupplying air to be conditioned to said conditioner, a plurality oi.induction units in said areas. at least one of said units serving eacharea to be conditioned. conduit means comprising tubes 01' a diameter ofthe order of six inches and connecting said units with said conditioner,means for delivering conditioned air for ventilation irom saidconditioner into said conduit means and for routing said conditioned airtherethrough at a static pressure in excess or 1" water gauge and at avelocity of the order of 3000 to 5000 feet per minute, means in each ofsaid units including a plurality of nozzles for discharging saidconditioned air within said units at relatively high velocity, means forsupplying within the units other air from the conditioned areas inducedby the high velocity discharge of conditioned air within the units, saidother air being induced in volume suiilcient when mixed with theconditioned air to take care of the circulation requirements of theconditioned areas whereby the use of return ducts to said conditioner iseliminated and said tubes limited in size in the ventilationrequirements of said areas, means for discharging said conditioned airand said induced air from each unit into the area served thereby, meansfor passing a conditioning medium in heat exchange relation with saidair through said conditioner, and means for conditioning medium in heatexchange relation with air in said units.

2. In an apparatus according to claim 1, a supply of conditioningmedium, a fluid circuit tor supplyin conditioning medium from saidsupply to the conditioner, another fluid circuit for supplyingconditioning medium to said units. and means automatically operativemponsive to variations in temperature conditions for varying thecirculation of conditioning medium routed to said units wherebydiil'erent areas served by difi'erent units will be maintained atdiiierent temperature conditions.

3. In an apparatus according to claim 1, valve means operativelyconnected to said units and adapted to control the circulation ofconditioning medium through said units, and a thermo-responsive controlelement regulating the operation 0! said valve means, said controlelement being disposed within a unit in the path of induced air passinginto the unit.

WILLIS H. CARRIER.

CERTIFICATE OF CORRECTION.

Patent No 2, 5 ,291i.

November 21, 191 h.

WILLIS H. csnnmn.

It is hereby certified that error appears in flee above numbered patentrequiring correction as follows: In the heading to the printedspecification, line 6, for the serial number "389,7h9 read --289,7l .9-;and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Office.

Signed and sealed an 25th day of September, A. D. 19%.

(Seal) Leslie Frazer First Assistant Commissioner of Patents.-

connection therewith when the number of units in operation isconsiderably varied from time to time, no detailed description thereofis deemed required here.

Since many changes may be made in the invention without departing fromthe scope thereof, it is intended that all matter set forth in the abovedescription, or shown in the accompanying drawings. be regarded asillustrative only and not in a limiting sense.

I claim:

I. In an apparatus of the character described for conditioning aplurality areas, a conditioner remote from said areas, means forsupplying air to be conditioned to said conditioner, a plurality oi.induction units in said areas. at least one of said units serving eacharea to be conditioned. conduit means comprising tubes 01' a diameter ofthe order of six inches and connecting said units with said conditioner,means for delivering conditioned air for ventilation irom saidconditioner into said conduit means and for routing said conditioned airtherethrough at a static pressure in excess or 1" water gauge and at avelocity of the order of 3000 to 5000 feet per minute, means in each ofsaid units including a plurality of nozzles for discharging saidconditioned air within said units at relatively high velocity, means forsupplying within the units other air from the conditioned areas inducedby the high velocity discharge of conditioned air within the units, saidother air being induced in volume suiilcient when mixed with theconditioned air to take care of the circulation requirements of theconditioned areas whereby the use of return ducts to said conditioner iseliminated and said tubes limited in size in the ventilationrequirements of said areas, means for discharging said conditioned airand said induced air from each unit into the area served thereby, meansfor passing a conditioning medium in heat exchange relation with saidair through said conditioner, and means for conditioning medium in heatexchange relation with air in said units.

2. In an apparatus according to claim 1, a supply of conditioningmedium, a fluid circuit tor supplyin conditioning medium from saidsupply to the conditioner, another fluid circuit for supplyingconditioning medium to said units. and means automatically operativemponsive to variations in temperature conditions for varying thecirculation of conditioning medium routed to said units wherebydiil'erent areas served by difi'erent units will be maintained atdiiierent temperature conditions.

3. In an apparatus according to claim 1, valve means operativelyconnected to said units and adapted to control the circulation ofconditioning medium through said units, and a thermo-responsive controlelement regulating the operation 0! said valve means, said controlelement being disposed within a unit in the path of induced air passinginto the unit.

WILLIS H. CARRIER.

CERTIFICATE OF CORRECTION.

Patent No 2, 5 ,291i.

November 21, 191 h.

WILLIS H. csnnmn.

It is hereby certified that error appears in flee above numbered patentrequiring correction as follows: In the heading to the printedspecification, line 6, for the serial number "389,7h9 read --289,7l .9-;and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Office.

Signed and sealed an 25th day of September, A. D. 19%.

(Seal) Leslie Frazer First Assistant Commissioner of Patents.-

